Intense tomato varieties, such as commercial varieties NUN 3155 TO F1 and NUN 3362 TO (Nunhems B.V.) comprise a mutation in an unknown gene (of which also the location in the genome was unknown), which converts the locular gel found in the seed cavities of tomato fruits into fleshy tissue. To see this “intense phenotype” the mutation needs to be present in homozygous form, i.e. the intense allele which confers the intense phenotype is recessive. As the mutant intense allele is present in the cultivated S. lycopersicum genome, which has a low degree of polymorphism in many genomic regions, it is difficult to map the responsible gene.
PCT/EP2013/055044 discloses a Solanum lycopersicum plant comprising a TYLCV resistance phenotype and an intense fruit phenotype, wherein said plant comprises at least one recombinant chromosome 6 comprising the recessive intense allele and an introgression fragment comprising an allele conferring TYLCV resistance in coupling configuration. This application shows that the recessive intense allele is located on chromosome 6 of Solanum lycopersicum, close to the locus of Ty-1 and Ty-3. This application does not show which gene, or genomic mutation, is responsible for the intense phenotype, nor does it show markers to identify the intense phenotype.
Tomato fruits with the intense phenotype have essentially no gel in the seed cavities surrounding the seeds and the locular gel (i.e. placenta tissue) is replaced by fleshy tissue. Such a phenotype is also of interest in breeding with other plant species having gel or non-fleshy tissue around the seeds.
A problem vegetable breeders are faced with is that no marker for the intense phenotype is known. Consequently, a breeder can only select plants with intense phenotype once the plant has mature fruit.
It is an object of the invention to find the genetic cause for the intense phenotype in tomato and to identify othologs of this gene in other plant species. It is also an object to provide tomato plants and plants of other species (especially cucumber and melon plants), which produce fruits having an intense phenotype, conferred by one or more mutations in the endogenous intense gene or ortholog of the gene, whereby said mutations lead to an altered expression, function or activity of the encoded protein. It is a further object to develop a marker that can be used in the selection of plants with an intense phenotype.